If various kinds of entire apparatuses can be formed on one semiconductor substrate, there are various advantages such as production simplification, but in actual circuits, there are circuits suitable for transformation-into-semiconductor, circuits not suitable for transformation-into-semiconductor, or circuits which are impossible to transform them into semiconductors. For this reason, plenty of external components besides one or plural semiconductor devices which are constituted by using a semiconductor substrate are required. For example, in the case of a receiver, a high frequency circuit where a tuning circuit using a capacitor and a coil is included is prepared as a separate component, all or some of subsequent stages of circuits are formed as a semiconductor device on a semiconductor substrate, and the receiver is constituted by connecting these on a printed circuit board.
Generally, a pad formed on a semiconductor substrate is used so as to connect a preceding stage of circuit and a subsequent stage of semiconductor device in this manner.
FIG. 2 is a diagram showing a conventional connection status of a tuning circuit and a semiconductor device connected in its subsequent stage. A parallel resonance circuit consisting of a coil and variable capacitance diodes is included in a tuning circuit 200, and a tuning frequency is changed by changing a reverse bias of tuning voltage applied to the variable capacitance diodes. In addition, in a semiconductor device 210 connected in the subsequent stage of this tuning circuit 200, a pad 214 into which an output signal of the tuning circuit 200 is inputted, and a pad 216 for applying a tuning voltage to the variable capacitance diodes in the tuning circuit 200 are formed on a semiconductor substrate 212.
By the way, as mentioned above, in the semiconductor device 210, two pads 214 and 216 used for connection between with one tuning circuit 200 are required. In particular, in a general receiver, there was a problem that, since two or more sets of parallel resonance circuits by a coil and variable capacitance diodes which were provided in the tuning circuit 200 were provided, the number of the pads for tuning circuits formed on the semiconductor substrate 212 was required twice of the number of these parallel resonance circuits, and hence, an area which these pads occupied became large. In particular, although the number of pads for outputting and inputting signals among plenty of external components increases when the high densification and functionality of the semiconductor device 210 are achieved, in order to miniaturize the semiconductor device 210, it is desired to reduce the number of pads formed on the semiconductor substrate 212, and in particular, the number of pads for tuning circuits with a large ratio among them.